The present invention relates to a moisture curable composition, and more particularly to a curable composition containing a hydrolyzable silyl group-containing vinyl polymer and having well balanced pot life and curability.
It is known that a silyl group-containing vinyl polymer having on the polymer chain end or the side chain thereof at least one silicon atom, to which a hydrolyzable group is linked, per one polymer molecule is curable by moisture, and is useful for providing a moisture curable composition. A composition containing the hydrolyzable silyl group-containing vinyl polymer and a hardener or curing catalyst such as an organo tin compound, an amine compound, an acidic compound or an acid phosphite compound is curable at low temperatures by moisture in the atmosphere to form a network structure, thus forming a cured product having excellent gloss, weathering resistance, discoloration resistance, solvent resistance, water resistance, heat resistance and hardness. It is possible to use the composition in various purposes, e.g. paint, adhesive, coating material and sealant, by utilizing the above excellent characteristics.
The curing characteristic of the hydrolyzable silyl group-containing vinyl polymer is greatly affected by the kinds of hardeners used, and accordingly selection of the hardeners suited for the purposes is indispensable. For instance, a paint composition containing the hydrolyzable silyl group-containing vinyl polymer, an acid phosphite compound and a solvent is poor in balance between the pot life, the curability and the appearance of the cured product, and may cause problems in practical use. That is to say, when the content of the acid phosphite compound is decreased, the pot life and the appearance are satisfactory, but the curability is poor. On the other hand, when the content of the acid phosphite compound is increased, the curability is satisfactory for practical use, but the pot life and the appearance are remarkably lowered.
It is an object of the present invention to provide a curable composition which has well balanced pot life and curability and provides a cured product having a good appearance.
A further object of the invention is to provide a curable composition, the curing characteristic of which can be arbitrarily controlled according to the purposes.
These and other objects of the present invention will become apparent from the description hereinafter.